Title:Dilepton creation based on an analytic hydrodynamic solution

Abstract: High-energy collisions of various nuclei, so called ``Little Bangs'' are
observed at various experiments of heavy ion colliders. The time evolution of
the strongly interacting quark-gluon plasma created in heavy ion collisions can
be described by hydrodynamical models. After expansion and cooling, the hadrons
are created in a freeze-out. Their distribution describes the final state of
this medium. To investigate the time evolution one needs to analyze penetrating
probes, such as direct photon or dilepton observables, as these particles are
created throughout the evolution of the medium. In this paper we analyze an 1+3
dimensional analytic solution of relativistic hydrodynamics, and we calculate
dilepton transverse momentum and invariant mass distributions. We investigate
the dependence of dilepton production on time evolution parameters, such as
emission duration and equation of state. Using parameters from earlier fits of
this model to photon and hadron spectra, we compare our calculations to
measurements as well. The most important feature of this work is that dilepton
observables are calculated from an exact, analytic, 1+3D solution of
relativistic hydrodynamics that is also compatible with hadronic and direct
photon observables.